YAG precursor powder was prepared in the hydroxyhydrogel form. Dehydration kinetic study and rehydration experiment was carried out to know the behavior of water molecules and hydroxide bonds present in the hydroxyhydrogel network structure with temperature. Rate constants and activation energies for dehydration and dehydroxylation were evaluated by static thermogravimetry. Percent rehydration was determined at different heat treatment temperatures. The results obtained were explained, correlated to establish the thermal stability of hydroxyhydrogel network structure and finally supported by the FTIR analysis.